Itll take some time, but if gigyas doesnt come back or is hard to get a hold of (I dont know i havent tried) then this IMO is the most easy way to go on about it. 

Everyone print screens their inventories /Chests and post them as images here.. Someone else takes over the server, and well have to spawn in the items individually. 
Heck if whoever takes up the server feels like they cant be asked spawning in the stuff, give me admin rights and Ill do it for ya. You can remove me from admin afterwards.